JEE Mains · Physics · STD 12 - Ray optics and optical instruments
- JEE Mains 2024
- Hard
- MCQ
An effective power of a combination of \(5\) identical convex lenses which are kept in contact along the principal axis is \(25 \mathrm{D}\). Focal length of each of the convex lens is _______.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(20 \mathrm{~cm}\)
Step-by-step Solution
Detailed explanation
\(\text { We know that } P_{e q}=\Sigma P_i\)
\(\therefore \text { given all lenses are identical }\)
\(\therefore 5 P=25 D\)
\(\therefore P=5 D\)
\(\therefore \frac{1}{f}=5 \Rightarrow f=\frac{1}{5} \mathrm{~m}=20 \mathrm{~cm}\)
Hence option \((1)\)
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